[LES] The "road" scene in Wicked is fucking baffling

Okay, so, I feel like everyone should agree that Wicked having a scene where they explain why the Yellow Brick Road is colored yellow is obviously like, "My name is Brian, but I am no Hero"-tier writing. This isn't about that. Instead I just wanna ask "why yellow"?

Like, for context, this entire movie is about how people are racist to Elphaba because she is green. Over the course of the film, she comes to be proud of the fact that she's green. When asked about the Emerald City, she says she hopes to go there some day because the city is green. When she meets Oz (her personal hero), the man is even dressed in green. We then see Oz go "what color should this symbolic road for all the people of Oz be" and she goes "yellow".

What???

I mean okay, obviously the movie has to make the Yellow Brick Road yellow, because that's the color of the road. But then why even put this scene in here! It could've just been yellow already! Or, even better, she could've chosen green and then they could've decided to make it yellow anyways because the twist is that Oz is like fake-woke and was just using her for her magic. Hell, maybe it's the only non-green part of the city out of like, spite or something. But she shouldn't go "Hmm, yeah, I'll go with yellow". She's green!!! It's a green city!!! The movie is about green people!!!